Conventional Bravais lenses provide an enlarged image of a virtual object at the object's location. A Bravais lens is described in the book "Modern Optical Engineering, The Design of Optical Systems", Second Edition, page 272. The Bravais lens described in this book is not an apochromatic lens (i.e., it is not corrected for chromatic aberrations) and thus introduces color aberrations when forming an image. If such a Bravais lens is placed into a composite laser beam containing a plurality of coaxial laser beams of different wavelength, all converging to the same waist location, the Bravais lens would produce a plurality of enlarged laser beam waists. These enlarged laser beam waists would be positioned in different planes along the optical axis of the Bravais lens and thus would not be coplanar.
Further, a Bravais lens described in the above mentioned book is not adapted for use with laser beams. When such Bravais lens is placed into a converging input laser beam to create an image a first laser beam waist, the Bravais lens would produce an second enlarged beam waist at a different location than the first beam waist location. The amount of distance between two beam waist locations will depend on the speed of the input laser beam. Thus, if the beam waists are being reimaged by another optical system to form a final image, the final image may be out of focus when the Bravais lens is placed in front of this optical system.